This invention relates generally to the field of direct current electrical motors and generators that operate without the need for commutation and/or rectification, and more particularly to multi-rotor homopolar machines which derive their emf (electromotive force) from co-rotational magnets and metallic disk embodiment.
Back in 1831, Michael Faraday discovered that a cylindrical magnet suspended by a string and touching a mercury bath at the bottom could generate electricity while spinning along its axis if a second electrical contact was made at the periphery of the midpoint of the magnet. His experiment was a one-piece homopolar machine since the magnet and conductor were joined together. Such Faraday generators have also been called acyclic, unipolar or homopolar generators because no commutation or alternating of the magnetic poles is necessary for this machine in order to generate electricity.
The type of electrical output is most often direct current (DC) unless specific means are designed to provide an interruption of radial conduction and thus simulate alternating current (AC). Historically, DC was championed by Thomas Edison during the early part of the 20th century while at the same time AC was championed by Nikola Tesla and George Westinghouse. In the future, DC will be coming back into style with the emergence of ambient temperature superconductive cables. Therefore, highly efficient homopolar generators will be in demand to meet the future market demand for DC electricity.
Homopolar generators usually have a single disk or drum rotating in a stationary magnetic field with sliding contacts. The sliding contacts often present high resistance however. The construction and operation of homopolar machines for electric propulsion of marine vessels or railguns for example is already well known. Such machines include motors and generators wherein electrical current flows through a conductor situated in a magnetic field during rotation of the machine rotor.
In the case of a homopolar motor, the current will develop a Jxc3x97B force perpendicular to the direction of its flow through the conductor and that of the magnetic field. In the case of a homopolar generator, a voltage dependent on the rotational speed, magnetic field, and radius, is induced in a conductor moving within the magnetic field. When current is drawn from the homopolar generator, it also develops a Jxc3x97B force for the same reason as with the motor but is referred to as back torque or armature reaction. General reference information including basic principles used to reduce back torque can be found in The Homopolar Handbook by Thomas Valone (ISBN 0-9641070-1-5).
The prior art rarely includes a one-piece homopolar machines that rotate the magnet with the disk. Even more unknown is the concept of rolling contacts. Eliminating sliding contacts is shown in the xe2x80x9cPlanetary Homopolar Generator,xe2x80x9d IBM Technical Disklosure Bulletin, Vol. 17, No. 6, p. 1786-87, November, 1974, H. D. Varadarajan.
Using a conducting belt or rolling contacts to gather current from a magnetic field flux cutting rotor, there is an annular magnetic field through which the rotor executes a planetary motion.
The large stresses resulting from the centrifugal force of the massive, unbalanced planetary rotor is a distinct disadvantage, prohibiting high speed operation. Thus, only a low rate of rotation is possible with the IBM design.
The xe2x80x9cDirect Current Homopolar Machinexe2x80x9d U.S. Pat. No. 5,587,618 to Hathaway demonstrates an analogous concept of relative motion between conductive orbiting shaft and a stationary disk-shaped magnetized armature.
However, the design is a bit cumbersome to be practical. Science Applications International Corporation claims a conductive belt, dual disk xe2x80x9cHomopolar Motor-Generatorxe2x80x9d in U.S. Pat. No. 5,241,232 to Reed that apparently reinvents the xe2x80x9cDynamo Electric Machinexe2x80x9d of U.S. Pat. No. 406,968 patented by none other than Nikola Tesla in 1889 that also has two unipolar magnetized rotors connected by a conductive belt. The belted dual unipolar machines solve one of the problems that plague the field by offering two sliding contacts at the low speed surface on the axle. However, the present invention requires only one sliding contact on the axle. These conductive belt machines also demonstrate, in principle, the concept of a multi-rotor, planetary design, by the process of coordinate transformation, since relative motion is the key to the operation of a homopolar generator. The concept of rolling contact is demonstrated with the Dalen xe2x80x9cDynamo Electric Machinexe2x80x9d U.S. Pat. No. 645,943, where two disks are turning in opposite directions while in contact with each other at their periphery. However, the axle of each disk must remain fixed in place whereas each axle is in orbiting motion in the present invention.
Homopolar machines can reversibly function as motors as well, such as flywheels, and used as energy storage devices. First used in transportation applications in the 1950""s, flywheel powered buses were designed to have the flywheel accelerated at every stop. Composite rotors currently have been developed which can spin at very high revolutions (100,000 revolutions per second); and the speed is limited by the tensile strength of the rim of the rotor. By using a multi-rotor design, the centrifugal forces of a large disk can be greatly reduced and still maintain high-energy storage or production. By using magnetic bearings, the friction on the axis of the rotor can be reduced sufficiently so that such rotors can maintain most of the energy for several days.
The IBM Varadarajan planetary rotor is unbalanced and has a low rate of magnetic flux cutting due to its annular magnetic field design. The Hathaway direct current machine has a lot of unbalanced conductive material orbiting the central magnetized disk which limits the rotational speed.
The conductive belt designs can be subject to oxidation and slippage, even requiring a toothed timing belt on each axle as well. With most disk models of homopolar generators, as opposed to drum designs, sliding contacts are the single most important contribution of resistance inhibiting the power output of the machine. Internal resistance is the only limit to the output capability of a homopolar generator and it is important to reduce all sources of internal resistance to obtain maximum power output for a given input torque. Rather than use high resistance carbon brushes, medium resistance silver-graphite brushes or dangerous conductive liquids such as mercury, low temperature solder, or sodium-potassium, there is a need to eliminate frictional sliding contact at the high speed periphery of the magnetized rotor completely. Furthermore, rather than maintaining two sliding contacts which contribute friction and resistance, even in the rolling and belted designs, there is a need to cut the number in half to only one high current sliding contact. The present invention satisfies both of these needs.
The present invention derives direct current electricity by co-rotating a plurality of magnets and a metallic disk. It comprises an improved homopolar machine with dynamically balancing, axially parallel, cylindrical, electrically conductive magnets arranged circumferentially around the vertical axis of central stator ring. Such a design can be referred to as distributed generation since each magnet rotor generates only a fraction of the current that is transmitted through the machine. Thus, the conductive bearings contacting the center of each end of the magnet rotors may carry only one tenth or less of the total current.
The multi-rotor orbiting homopolar also does not include sliding contacts at each magnetized rotor rim but instead utilizes a suitable rolling means attached separately to magnets and also to the stator ring for intimately contacting and engaging non-slip rolling between magnets and stator as they orbit around the stator. The magnetized rotors maintain rotational synchronism and equal relative position to each other with a bearing means rotatably securing the top and bottom end of each magnet to a corresponding electrically conductive circular endplate.
The electrical energy is extracted, or input if used as a motor, through contacts on the conductive stator and at the machine""s electrically conductive axle located in the center of the machine while rigidly attached to the top circular endplate that rotates with all of the individually magnetized rotors. The only single, high current, moving contact that is required is an electrically conductive thrust bearing that supports the central axle. An insulating thrust bearing meanwhile separates the axle from the center of bottom circular endplate. The stator, which is of course stationary, accomplishes the second contact means through a standard electrical connection with no need for any relative motion sliding contact. The stator may be optionally magnetized in the opposite direction to the magnetized rotors in order to increase the coercive force or magnetic flux density.
The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention.
The problem this invention solves is that it generates high power direct current electricity without the need for commutation and rectification, otherwise the internal resistance losses are high.
The problems with prior art devices, processes and systems can be categorized as follows.
1. Require commutation or rectification to generate direct current electricity.
2. Rely on more than one current brush which often have high speed contact.
3. Do not distribute magnetic field power generation by multi-rotor orbiting magnets in homopolar machines or systems.
4. Internal resistance losses are usually high.
5. Neither efficient nor cost effective.
6. Neither simple nor practical for most applications.
A preliminary limited prior art search was not commissioned but the inventor is intimately familiar with the prior art. Following are typical examples of the prior art arranged in reverse chronological order for ready reference of the reader.
11) Non-Provisional Utility U.S. Pat. No. 6,051,905 issued to Richard Clark on Apr. 18, 2000 for xe2x80x9cHomopolar Generatorxe2x80x9d
10) Non-Provisional Utility U.S. Pat. No. 5,977,684 presented to Ted Lin on Nov. 2, 1999 for xe2x80x9cRotating Machine Configurable as True DC Generator or Motorxe2x80x9d
09) Non-Provisional Utility U.S. Pat. No. 5,864,198 earned by Joseph Pinkerton on Jan. 26, 1999 for xe2x80x9cBrushless Generatorxe2x80x9d
08) Non-Provisional Utility U.S. Pat. No. 5,587,618 issued to George Hathaway on Dec. 24, 1996 for xe2x80x9cDirect Current Homopolar Machinexe2x80x9d
07) Non-Provisional Utility U.S. Pat. No. 5,278,470 graced upon Zacharias Neag on Jan. 11, 1994 for xe2x80x9cHomopolar Machine which acts as a Direct Current (DC) High Voltage Generator or Motorxe2x80x9d
06) Non-Provisional Utility U.S. Pat. No. 5,241,232 honorably given to Jay Reed on Aug. 31, 1993 for xe2x80x9cHomopolar Motor-Generatorxe2x80x9d
05) Non-Provisional Utility U.S. Pat. No. 5,011,821 published in the name of Charley McCullough on Apr. 30, 1991 for xe2x80x9cMethod and Apparatus for Generating Electricityxe2x80x9d
04) Non-Provisional Utility U.S. Pat. No. 3,465,187 issued to Onezime Breaux on Sep. 2, 1969 for xe2x80x9cHomopolar Generator Having Parallel Positioned Faraday Disk Structuresxe2x80x9d
03) Non-Provisional Utility U.S. Pat. No. 3,185,877 presented to Anthony Sears on May 25, 1965 for xe2x80x9cDirect Current Homopolar Generatorxe2x80x9d
02) Non-Provisional Utility U.S. Pat. No. 645,943 graced upon inventor Gustaf Dalen on Mar. 27, 1900 for xe2x80x9cDynamo Electric Machinexe2x80x9d
01) Non-Provisional Utility U.S. Pat. No. 406,968 bestowed upon none other than Nikola Tesla himself in 1889 for xe2x80x9cDynamo Electric Machinexe2x80x9d
None of the prior art devices known to the applicant or his attorney disclose the EXACT embodiment of this inventor that constitutes a simple, elegant and affordable system for an orbiting Multi-Rotor Homopolar direct current electricity generation
Unfortunately none of the prior art devices singly or even in combination provide for all of the objectives as established by the inventor for this system as enumerated below.
1. It is an objective of this invention to provide devices, method and system for generation of high power direct current electricity without commutation and rectification.
2. The primary objective of the invention is orbiting multi-rotor cylindrical magnets in rolling contact that eliminates friction while generating DC electricity.
3. Another objective of the invention is to provide high efficiency, low noise and low resistance in a high current generator.
4. Another objective of the invention is that it uses readily available materials in a dynamically balanced arrangement.
5. Another objective of the invention is safety through reduced internal stress than comparable homopolar machines with a single rotor.
6. Another objective of the invention is that it provides distributed generation around an air core.
7. Another objective of this invention is to provide an easy, quick, simple practical way to generate more efficient and cost effective direct current electricity.
8. Another objective of this invention is that it promote and encourage other inventors to do additional research in homopolar machines generally but co-rotational magnets and disk embodiments in particular.
9. Another objective of this invention is to provide a system that is integrated and flexible.
10. Another objective of this invention is to provide a system that is easily useable and requires little if any training for manufacturing and use.
11. Another objective of this invention is that it meet all federal, state, local and other private standards guidelines, regulations and recommendations with respect to safety, environment, and energy consumption.
12. Another objective of this invention is that it can be made from modular standard materials and components that are also easily maintainable.
Other objectives advantages and features of this invention reside in its simplicity, elegance of design, ease of manufacture, service and use and even aesthetics as will become apparent from the following brief description of the drawings and the detailed description of the best mode preferred embodiments taken in connection with the accompanying drawings.